javascript - 创建对象时如何在属性中给出数组索引

Question

我正在 javascript a 中创建一个基于一些数组数据的对象

var myArr = [
    {
        "id": 1,
        "Music": "POP",
        "Singer": "Abc",
        "Country": "IND"
    },
    {
        "id": 2,
        "Music": "JAZZ",
        "Singer": "xyz",
        "Country": "USA"
    },
    {
        "id": 3,
        "Music": "BLUES",
        "Singer": "def",
        "Country": "ENG"
    }
]

现在基于这个数组，我尝试创建一个具有以下内容的数组对象

id、值和国家/地区。

这是我正在尝试的

var myObj = [];

for (var i = 0; i < myArr.length; i++) {
    var obj = {
        id: i,
        Value: myArr[i].Music,
        myArr[i].Singer : myArr[i].Country,
    }
    myObj.push(obj);
}

但是在此 for 循环期间 myArr[i].Singer 抛出错误。怎么解决这个问题。

Answer 1

对于数组，获取所需的键并直接在对象字面量之外分配值。

var myArr = [{ id: 1, Music: "POP", Singer: "Abc", Country: "IND" }, { id: 2, Music: "JAZZ", Singer: "xyz", Country: "USA" }, { id: 3, Music: "BLUES", Singer: "def", Country: "ENG" }],
    myObj = [],
    obj;

for (var i = 0; i < myArr.length; i++) {
    obj = {
        id: i,
        Value: myArr[i].Music
    }
    obj[myArr[i].Singer] = myArr[i].Country;
    myObj.push(obj);
}

console.log(myObj);

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使用 ES6，您可以使用 computed property names并将该对象映射为新数组。

var array = [{ id: 1, Music: "POP", Singer: "Abc", Country: "IND" }, { id: 2, Music: "JAZZ", Singer: "xyz", Country: "USA" }, { id: 3, Music: "BLUES", Singer: "def", Country: "ENG" }],
    result = array.map((o, i) => ({ id: i, Value: o.Music, [o.Singer]: o.Country}));

console.log(result);

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